Deserto translates to "deserted" or "empty." While it can refer to a physical desert, in this song, it's used metaphorically to describe a heart that feels barren and longing.
The lyrics state, "Nace de un corazón que esta deserto" (It's born from a heart that is deserted). This word is interesting because it paints a vivid picture of emotional emptiness, setting the stage for the singer to reveal deep secrets and desires that will fill this void.